This invention relates to firearms, and it relates more particularly to cylinder-locking devices for revolvers and to actuating means for unlocking the cartridge cylinder so that it can be indexed while the hammer is being cocked.
The cylinder in a revolver is rotated through a predetermined angle of rotation by means of a pawl and ratchet arrangement, the pawl or cylinder hand, as it is sometimes called, being actuated when the trigger is pulled to engage a tooth of the ratchet located on the rear face of the cylinder. As each cartridge chamber in the cylinder is brought into alignment with the bore in the barrel of the revolver by means of the pawl and ratchet, it is locked in such aligned position while the cartridge is fired and, upon return of the trigger to its forward position, the pawl is returned to its initial position where it is ready to engage the next ratchet tooth, whereby the cylinder is successively indexed from one cartridge chamber to the next each time the trigger is pulled.
In order to stop the cylinder as each chamber is brought into alignment with the barrel and to hold it in such alignment until the trigger is pulled again, a cylinder stop or lock retractably mounted in the frame of the revolver moves into locking engagement with one of a series of stop notches provided on the periphery of the cylinder. When the trigger is pulled, the cylinder lock is first retracted from one of the stop notches in the cylinder to permit the cylinder to be rotated and, when the cylinder is indexed through the required number of degrees, the lock is again moved into engagement with the next stop notch to hold the cylinder in the next position. The cylinder lock remains thus engaged when the gun is fired and when the trigger is released, therby preventing rotation of the cylinder at all times except while it is being indexed from one chamber to the next.
As a general rule it is desirable to provide the cylinder lock with a relatively heavy spring for urging it into locking engagement with the cylinder, both to prevent throw-by of the cylinder when it is indexed rapidly from one chamber to the next and to prevent accidental release of the cylinder when the revolver is not actually being fired. Furthermore, use of a heavy cylinder-lock spring is particularly desirable in a cylinder-indexing system disclosed in the U.S. patent to Baker U.S. Pat. No. 4,001,962, for which the present cylinder-locking device was more particularly designed, because of the unique camming action of the lock on the cylinder employed in the Baker system which assures accurate indexing of the cylinder.
Typical cylinder locks which work in the manner outlined above are disclosed in the U.S. patents to Sefried U.S. Pat. No. 2,958,151, and to Baker U.S. Pat. Nos. 3,996,686 and 4,001,962.
However, in all prior cylinder-locking systems of which I am aware, the heavier the locking spring is, the greater the force required to return the trigger from its firing position to its rest position. This is due to the fact that the locking spring usually has to be compressed during the return stroke of the trigger, and revolvers which have been provided with a heavy locking spring have necessarily had to employ a rather heavy trigger-return spring. The obvious disadvantage of this is that the trigger pull is undesirably heavy. While the existence of a heavy trigger spring may not be particularly important in some double-action revolvers because of the great force required in cocking the hammer by means of the trigger, it is a distinct disadvantage where the revolver can be fired--even in double action--by means of only a relatively light trigger-pull. Moreover, when firing in single-action, it is of course particularly desirable for shooting accuracy to provide a smooth and relatively light trigger-pull.
As a practical matter, therefore, in order to obtain the desired trigger-pull, it has been necessary to reduce the strength of the cylinder-locking spring below what would otherwise be desirable for functional, as well as safety, purposes. An important object of the present invention is to provide a way of unlocking the cartridge cylinder of a double-action revolver, which does not interfere with the return of the trigger to its rest position, so that a much heavier cylinder-lock spring can be used.
On the other hand, even in those rare cases where a separate trigger spring is unnecessary, use of a heavy cylinder-lock spring usually resulted in an unacceptable trigger-pull. It is accordingly an object of this invention to provide sufficient mechanical leverage between the trigger and the cylinder lock by means of a toggle action for overcoming the pressure of a heavy cylinder-lock spring when the lock is retracted by the trigger in order to release the cylinder for indexing.
These and other objects and advantages of the invention will become more readily apparent from the specific description hereinafter of one embodiment of the invention.